Holly has been used as a holy plant in religious rituals around the world, from tribal to pagan to Christian, for many centuries. It was both displayed as a protection and consumed as a hallucinogen in a wide range of cultures.

In Celtic mythology the Holly King was said to rule over the half of the year from the summer to the winter solstice, at which time the Oak King defeated the Holly King to rule for the time until the summer solstice again. These two aspects of the Nature god were later incorporated into the Mummers' plays traditionally performed around Yuletide. The Holly King was depicted as a powerful giant of a man covered in holly leaves and branches, and wielding a holly bush as a club.

Although the felling of whole holly trees was said to bring bad luck, the taking of boughs for decoration, and the coppicing of trees to provide winter fodder, was allowed. Both a male and female holly are needed in landscape planting in order for winter berries to be produced which can be red, white or yellow berries.

Holly trees were traditionally thought to provide protection from lightning strikes, often purposely planted near houses. In related European mythology, holly was associated with thunder gods such as Thor and Taranis.

Interestingly, holly makes several different kinds of leaves, all genetically the same but with a different response to the combined result of animals browsing on them (or hedge trimmers) and the trees' swift response!